A conventional electrophoretic display medium well known in the art is provided with a dispersion medium injected between pair of substrates with positive or negative charged particles dispersed therein so as to display an image. In such an electrophoretic display medium, a pair of substrates is disposed to face each other. With the application of an electric field, charged particles migrate between the substrates, thereby displaying an image.
There provided in such an electrophoretic display medium are a partition that partitions the region between the substrates, and a spacer disposed on the outer circumference of a substrate for defining the distance between the substrates.
Patent document 1 discloses such an electrophoretic display medium in which a spacer and a partition are disposed between substrates.
Patent Document 1: Japanese Utility Model Application Publication No. S56-108171
In order to manufacture such an electrophoretic display medium having a partition and a spacer, following methods are available. One method is to form a spacer on an outer circumference of a substrate, followed by forming a partition in a region inside the spacer formed on the outer circumference. The other method is to form a partition on a substrate, followed by forming a spacer on an outer circumference of the substrate so as to enclose the partition. In these methods, an adhesive is applied between the partition and the substrate so that the partition and the substrate are fixed together persistently. In order to fix the spacer and the substrate together persistently, an adhesive is also applied between the spacer and the substrate.
However, in such an electrophoretic display medium, if there is a demand that the partition be lower than the spacer, it is difficult to make a level difference between the partition and the spacer accurately in the above method where the partition and the spacer formed separately are mounted on the substrate. This is because of the difficulty in having an accurate control over the adhesive thickness between the partition and the substrate as well as between the spacer and the substrate.
The present invention is made to solve the above problem, and it is an object of the present invention to provide a method of allowing a partition and a spacer of different heights to be formed on a substrate accurately, and an electrophoretic display medium where a partition and a spacer of different heights are formed accurately.